SQLite

/* Unsigned integer types */
typedef sqlite3_uint64 u64;
typedef unsigned int u32;
typedef unsigned char u8;

/* Objects */
typedef struct JsonString JsonString;
typedef struct JsonNode JsonNode;
typedef struct JsonParse JsonParse;

/* An instance of this object represents a JSON string
** under construction.  Really, this is a generic string accumulator
** that can be and is used to create strings other than JSON.
*/
struct JsonString {
  sqlite3_context *pCtx;   /* Function context - put error messages here */
  char *zBuf;              /* Append JSON content here */
  u64 nAlloc;              /* Bytes of storage available in zBuf[] */
  u64 nUsed;               /* Bytes of zBuf[] currently used */
  u8 bStatic;              /* True if zBuf is static space */
  u8 bErr;                 /* True if an error has been encountered */
  char zSpace[100];        /* Initial static space */

  u8 eType;              /* One of the JSON_ type values */
  u8 jnFlags;            /* JNODE flags */
  u8 iVal;               /* Replacement value when JNODE_REPLACE */
  u32 n;                 /* Bytes of content, or number of sub-nodes */
  union {
    const char *zJContent; /* Content for INT, REAL, and STRING */
    u32 iAppend;           /* More terms for ARRAY and OBJECT */
    u32 iKey;              /* Key for ARRAY objects in json_tree() */
  } u;
};

/* A completely parsed JSON string
*/
struct JsonParse {
  u32 nNode;         /* Number of slots of aNode[] used */
  u32 nAlloc;        /* Number of slots of aNode[] allocated */
  JsonNode *aNode;   /* Array of nodes containing the parse */
  const char *zJson; /* Original JSON string */
  u32 *aUp;          /* Index of parent of each node */
  u8 oom;            /* Set to true if out of memory */
};


/**************************************************************************
** Utility routines for dealing with JsonString objects
**************************************************************************/









/* Set the JsonString object to an empty string
*/
static void jsonZero(JsonString *p){
  p->zBuf = p->zSpace;
  p->nAlloc = sizeof(p->zSpace);
  p->nUsed = 0;
  p->bStatic = 1;
}

/* Initialize the JsonString object
*/
static void jsonInit(JsonString *p, sqlite3_context *pCtx){
  p->pCtx = pCtx;
  p->bErr = 0;
  jsonZero(p);
}


/* Free all allocated memory and reset the JsonString object back to its
** initial state.
*/
static void jsonReset(JsonString *p){
  if( !p->bStatic ) sqlite3_free(p->zBuf);
  jsonZero(p);
}


/* Report an out-of-memory (OOM) condition 
*/
static void jsonOom(JsonString *p){
  if( !p->bErr ){
    p->bErr = 1;
    sqlite3_result_error_nomem(p->pCtx);
    jsonReset(p);
  }
}

/* Enlarge pJson->zBuf so that it can hold at least N more bytes.
** Return zero on success.  Return non-zero on an OOM error
*/
static int jsonGrow(JsonString *p, u32 N){
  u64 nTotal = N<p->nAlloc ? p->nAlloc*2 : p->nAlloc+N+10;
  char *zNew;
  if( p->bStatic ){
    if( p->bErr ) return 1;
    zNew = sqlite3_malloc64(nTotal);
    if( zNew==0 ){
      jsonOom(p);

    }
    p->zBuf = zNew;
  }
  p->nAlloc = nTotal;
  return SQLITE_OK;
}

/* Append N bytes from zIn onto the end of the JsonString string.
*/
static void jsonAppendRaw(JsonString *p, const char *zIn, u32 N){
  if( (N+p->nUsed >= p->nAlloc) && jsonGrow(p,N)!=0 ) return;
  memcpy(p->zBuf+p->nUsed, zIn, N);
  p->nUsed += N;
}

#ifdef SQLITE_DEBUG
/* Append the zero-terminated string zIn
*/
static void jsonAppend(JsonString *p, const char *zIn){
  jsonAppendRaw(p, zIn, (u32)strlen(zIn));
}
#endif

/* Append a single character
*/
static void jsonAppendChar(JsonString *p, char c){
  if( p->nUsed>=p->nAlloc && jsonGrow(p,1)!=0 ) return;
  p->zBuf[p->nUsed++] = c;
}

/* Append a comma separator to the output buffer, if the previous
** character is not '[' or '{'.
*/
static void jsonAppendSeparator(JsonString *p){
  char c;
  if( p->nUsed==0 ) return;
  c = p->zBuf[p->nUsed-1];
  if( c!='[' && c!='{' ) jsonAppendChar(p, ',');
}

/* Append the N-byte string in zIn to the end of the JsonString string
** under construction.  Enclose the string in "..." and escape
** any double-quotes or backslash characters contained within the
** string.
*/
static void jsonAppendString(JsonString *p, const char *zIn, u32 N){
  u32 i;
  if( (N+p->nUsed+2 >= p->nAlloc) && jsonGrow(p,N+2)!=0 ) return;
  p->zBuf[p->nUsed++] = '"';
  for(i=0; i<N; i++){
    char c = zIn[i];
    if( c=='"' || c=='\\' ){
      if( (p->nUsed+N+1-i > p->nAlloc) && jsonGrow(p,N+1-i)!=0 ) return;
      p->zBuf[p->nUsed++] = '\\';
    }
    p->zBuf[p->nUsed++] = c;
  }
  p->zBuf[p->nUsed++] = '"';
}

/*
** Append a function parameter value to the JSON string under 
** construction.
*/
static void jsonAppendValue(
  JsonString *p,                 /* Append to this JSON string */
  sqlite3_value *pValue          /* Value to append */
){
  switch( sqlite3_value_type(pValue) ){
    case SQLITE_NULL: {
      jsonAppendRaw(p, "null", 4);
      break;
    }

    }
  }
}


/* Make the JSON in p the result of the SQL function.
*/
static void jsonResult(JsonString *p){
  if( p->bErr==0 ){
    sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed, 
                          p->bStatic ? SQLITE_TRANSIENT : sqlite3_free,
                          SQLITE_UTF8);
    jsonZero(p);
  }
  assert( p->bStatic );
}

/**************************************************************************
** Utility routines for dealing with JsonNode and JsonParse objects
**************************************************************************/

/*
** Return the number of consecutive JsonNode slots need to represent
** the parsed JSON at pNode.  The minimum answer is 1.  For ARRAY and
** OBJECT types, the number might be larger.
**
** Appended elements are not counted.  The value returned is the number
** by which the JsonNode counter should increment in order to go to the
** next peer value.
*/
static u32 jsonNodeSize(JsonNode *pNode){
  return pNode->eType>=JSON_ARRAY ? pNode->n+1 : 1;
}

/*
** Reclaim all memory allocated by a JsonParse object.  But do not
** delete the JsonParse object itself.
*/
static void jsonParseReset(JsonParse *pParse){
  sqlite3_free(pParse->aNode);
  pParse->aNode = 0;
  pParse->nNode = 0;
  pParse->nAlloc = 0;
  sqlite3_free(pParse->aUp);
  pParse->aUp = 0;
}

/*
** Convert the JsonNode pNode into a pure JSON string and
** append to pOut.  Subsubstructure is also included.  Return
** the number of JsonNode objects that are encoded.
*/
static void jsonRenderNode(
  JsonNode *pNode,               /* The node to render */
  JsonString *pOut,              /* Write JSON here */
  sqlite3_value **aReplace       /* Replacement values */
){
  switch( pNode->eType ){
    case JSON_NULL: {
      jsonAppendRaw(pOut, "null", 4);
      break;
    }

              jsonAppendSeparator(pOut);
              jsonAppendValue(pOut, aReplace[pNode[j].iVal]);
            }
          }else{
            jsonAppendSeparator(pOut);
            jsonRenderNode(&pNode[j], pOut, aReplace);
          }
          j += jsonNodeSize(&pNode[j]);
        }
        if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
        pNode = &pNode[pNode->u.iAppend];
        j = 1;
      }
      jsonAppendChar(pOut, ']');
      break;

            jsonAppendChar(pOut, ':');
            if( pNode[j+1].jnFlags & JNODE_REPLACE ){
              jsonAppendValue(pOut, aReplace[pNode[j+1].iVal]);
            }else{
              jsonRenderNode(&pNode[j+1], pOut, aReplace);
            }
          }
          j += 1 + jsonNodeSize(&pNode[j+1]);
        }
        if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
        pNode = &pNode[pNode->u.iAppend];
        j = 1;
      }
      jsonAppendChar(pOut, '}');
      break;

        zOut[j] = 0;
        sqlite3_result_text(pCtx, zOut, j, sqlite3_free);
      }
      break;
    }
    case JSON_ARRAY:
    case JSON_OBJECT: {
      JsonString s;
      jsonInit(&s, pCtx);
      jsonRenderNode(pNode, &s, aReplace);
      jsonResult(&s);
      break;
    }
  }
}

  pParse->zJson = zJson;
  i = jsonParseValue(pParse, 0);
  if( i>0 ){
    while( isspace(zJson[i]) ) i++;
    if( zJson[i] ) i = -1;
  }
  if( i<0 ){
    jsonParseReset(pParse);
    return 1;
  }
  return 0;
}

/* Mark node i of pParse as being a child of iParent.  Call recursively
** to fill in all the descendants of node i.
*/
static void jsonParseFillInParentage(JsonParse *pParse, u32 i, u32 iParent){
  JsonNode *pNode = &pParse->aNode[i];
  u32 j;
  pParse->aUp[i] = iParent;
  switch( pNode->eType ){
    case JSON_ARRAY: {
      for(j=1; j<=pNode->n; j += jsonNodeSize(pNode+j)){
        jsonParseFillInParentage(pParse, i+j, i);
      }
      break;
    }
    case JSON_OBJECT: {
      for(j=1; j<=pNode->n; j += jsonNodeSize(pNode+j+1)+1){
        pParse->aUp[i+j] = i;
        jsonParseFillInParentage(pParse, i+j+1, i);
      }
      break;
    }
    default: {
      break;
    }
  }
}

/*
** Compute the parentage of all nodes in a completed parse.
*/
static int jsonParseFindParents(JsonParse *pParse){
  u32 *aUp;
  assert( pParse->aUp==0 );
  aUp = pParse->aUp = sqlite3_malloc( sizeof(u32)*pParse->nNode );
  if( aUp==0 ) return SQLITE_NOMEM;
  jsonParseFillInParentage(pParse, 0, 0);
  return SQLITE_OK;
}

/* forward declaration */
static JsonNode *jsonLookupAppend(JsonParse*,const char*,int*);

/*
** Search along zPath to find the node specified.  Return a pointer
** to that node, or NULL if zPath is malformed or if there is no such

      while( j<=pRoot->n ){
        if( pRoot[j].n==nKey+2
         && strncmp(&pRoot[j].u.zJContent[1],zKey,nKey)==0
        ){
          return jsonLookup(pParse, iRoot+j+1, &zPath[i], pApnd);
        }
        j++;
        j += jsonNodeSize(&pRoot[j]);
      }
      if( (pRoot->jnFlags & JNODE_APPEND)==0 ) break;
      iRoot += pRoot->u.iAppend;
      pRoot = &pParse->aNode[iRoot];
      j = 1;
    }
    if( pApnd ){

      zPath++;
    }
    if( zPath[0]!=']' ) return 0;
    zPath++;
    j = 1;
    for(;;){
      while( i>0 && j<=pRoot->n ){
        j += jsonNodeSize(&pRoot[j]);
        i--;
      }
      if( (pRoot->jnFlags & JNODE_APPEND)==0 ) break;
      iRoot += pRoot->u.iAppend;
      pRoot = &pParse->aNode[iRoot];
      j = 1;
    }

** well-formed.
*/
static void jsonParseFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  JsonString s;       /* Output string - not real JSON */
  JsonParse x;        /* The parse */
  u32 i;
  char zBuf[100];

  assert( argc==1 );
  if( jsonParse(&x, (const char*)sqlite3_value_text(argv[0])) ) return;
  jsonInit(&s, context);
  for(i=0; i<x.nNode; i++){
    sqlite3_snprintf(sizeof(zBuf), zBuf, "node %3u: %7s n=%d\n",
                     i, jsonType[x.aNode[i].eType], x.aNode[i].n);
    jsonAppend(&s, zBuf);
    if( x.aNode[i].u.zJContent!=0 ){
      jsonAppendRaw(&s, "    text: ", 10);
      jsonAppendRaw(&s, x.aNode[i].u.zJContent, x.aNode[i].n);
      jsonAppendRaw(&s, "\n", 1);
    }
  }
  jsonParseReset(&x);
  jsonResult(&s);
}

/*
** The json_test1(JSON) function parses and rebuilds the JSON string.
*/
static void jsonTest1Func(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  JsonParse x;  /* The parse */
  if( jsonParse(&x, (const char*)sqlite3_value_text(argv[0])) ) return;
  jsonReturn(x.aNode, context, 0);
  jsonParseReset(&x);
}

/*
** The json_nodecount(JSON) function returns the number of nodes in the
** input JSON string.
*/
static void jsonNodeCountFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  JsonParse x;  /* The parse */
  if( jsonParse(&x, (const char*)sqlite3_value_text(argv[0])) ) return;
  sqlite3_result_int64(context, x.nNode);
  jsonParseReset(&x);
}
#endif /* SQLITE_DEBUG */

/****************************************************************************
** SQL function implementations
****************************************************************************/

/*
** Implementation of the json_array(VALUE,...) function.  Return a JSON
** array that contains all values given in arguments.  Or if any argument
** is a BLOB, throw an error.
*/
static void jsonArrayFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int i;
  JsonString jx;

  jsonInit(&jx, context);
  jsonAppendChar(&jx, '[');
  for(i=0; i<argc; i++){
    jsonAppendSeparator(&jx);
    jsonAppendValue(&jx, argv[i]);
  }

  if( jsonParse(&x, (const char*)sqlite3_value_text(argv[0]))==0 ){
    if( x.nNode ){
      JsonNode *pNode = x.aNode;
      if( zPath ) pNode = jsonLookup(&x, 0, zPath, 0);
      if( pNode->eType==JSON_ARRAY ){
        assert( (pNode->jnFlags & JNODE_APPEND)==0 );
        for(i=1; i<=pNode->n; n++){
          i += jsonNodeSize(&pNode[i]);
        }
      }
    }
    jsonParseReset(&x);
  }
  sqlite3_result_int64(context, n);
}

/*
** json_extract(JSON, PATH)
**

  if( zPath[0]!='$' ) return;
  zPath++;
  if( jsonParse(&x, (const char*)sqlite3_value_text(argv[0])) ) return;
  pNode = jsonLookup(&x, 0, zPath, 0);
  if( pNode ){
    jsonReturn(pNode, context, 0);
  }
  jsonParseReset(&x);
}

/*
** Implementation of the json_object(NAME,VALUE,...) function.  Return a JSON
** object that contains all name/value given in arguments.  Or if any name
** is not a string or if any value is a BLOB, throw an error.
*/
static void jsonObjectFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  int i;
  JsonString jx;
  const char *z;
  u32 n;

  if( argc&1 ){
    sqlite3_result_error(context, "json_object() requires an even number "
                                  "of arguments", -1);
    return;

      pNode = jsonLookup(&x, 0, &zPath[1], 0);
      if( pNode ) pNode->jnFlags |= JNODE_REMOVE;
    }
    if( (x.aNode[0].jnFlags & JNODE_REMOVE)==0 ){
      jsonReturn(x.aNode, context, 0);
    }
  }
  jsonParseReset(&x);
}

/*
** json_replace(JSON, PATH, VALUE, ...)
**
** Replace the value at PATH with VALUE.  If PATH does not already exist,
** this routine is a no-op.  If JSON is ill-formed, return NULL.

    }
    if( x.aNode[0].jnFlags & JNODE_REPLACE ){
      sqlite3_result_value(context, argv[x.aNode[0].iVal]);
    }else{
      jsonReturn(x.aNode, context, argv);
    }
  }
  jsonParseReset(&x);
}

/*
** json_set(JSON, PATH, VALUE, ...)
**
** Set the value at PATH to VALUE.  Create the PATH if it does not already
** exist.  Overwrite existing values that do exist.
** If JSON is ill-formed, return NULL.
**

    }
    if( x.aNode[0].jnFlags & JNODE_REPLACE ){
      sqlite3_result_value(context, argv[x.aNode[0].iVal]);
    }else{
      jsonReturn(x.aNode, context, argv);
    }
  }
  jsonParseReset(&x);
}

/*
** json_type(JSON)
** json_type(JSON, PATH)
**
** Return the top-level "type" of a JSON string.  Return NULL if the

  }
  if( jsonParse(&x, (const char*)sqlite3_value_text(argv[0])) ) return;
  if( x.nNode ){
    JsonNode *pNode = x.aNode;
    if( zPath ) pNode = jsonLookup(&x, 0, zPath, 0);
    sqlite3_result_text(context, jsonType[pNode->eType], -1, SQLITE_STATIC);
  }
  jsonParseReset(&x);
}

/****************************************************************************
** The json_each virtual table
****************************************************************************/
typedef struct JsonEachCursor JsonEachCursor;
struct JsonEachCursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  u32 iRowid;                /* The rowid */
  u32 i;                     /* Index in sParse.aNode[] of current row */
  u32 iEnd;                  /* EOF when i equals or exceeds this value */
  u8 eType;                  /* Type of top-level element */
  u8 bRecursive;             /* True for json_tree().  False for json_each() */
  char *zJson;               /* Input JSON */
  char *zPath;               /* Path by which to filter zJson */
  JsonParse sParse;          /* Parse of the input JSON */
};

/* Constructor for the json_each virtual table */
static int jsonEachConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3_vtab *pNew;

  int rc;

/* Column numbers */
#define JEACH_KEY    0
#define JEACH_VALUE  1
#define JEACH_TYPE   2
#define JEACH_ATOM   3
#define JEACH_ID     4
#define JEACH_PARENT 5
#define JEACH_JSON   6
#define JEACH_PATH   7

  rc = sqlite3_declare_vtab(db, 
     "CREATE TABLE x(key,value,type,atom,id,parent,json hidden,path hidden)");
  if( rc==SQLITE_OK ){
    pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) );
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
  }
  return rc;
}

/* destructor for json_each virtual table */
static int jsonEachDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
  return SQLITE_OK;
}

/* constructor for a JsonEachCursor object for json_each(). */
static int jsonEachOpenEach(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  JsonEachCursor *pCur;
  pCur = sqlite3_malloc( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/* constructor for a JsonEachCursor object for json_tree(). */
static int jsonEachOpenTree(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  int rc = jsonEachOpenEach(p, ppCursor);
  if( rc==SQLITE_OK ){
    JsonEachCursor *pCur = (JsonEachCursor*)*ppCursor;
    pCur->bRecursive = 1;
  }
  return rc;
}

/* Reset a JsonEachCursor back to its original state.  Free any memory
** held. */
static void jsonEachCursorReset(JsonEachCursor *p){
  sqlite3_free(p->zJson);
  sqlite3_free(p->zPath);
  jsonParseReset(&p->sParse);
  p->iRowid = 0;
  p->i = 0;
  p->iEnd = 0;
  p->eType = 0;

  p->zJson = 0;
  p->zPath = 0;
}

/* Destructor for a jsonEachCursor object */
static int jsonEachClose(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  jsonEachCursorReset(p);
  sqlite3_free(cur);
  return SQLITE_OK;
}

/* Return TRUE if the jsonEachCursor object has been advanced off the end
** of the JSON object */
static int jsonEachEof(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  return p->i >= p->iEnd;
}

/* Advance the cursor to the next element for json_tree() */
static int jsonEachNextTree(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  if( p->i==0 ){
    p->i = 1;
  }else if( p->sParse.aNode[p->sParse.aUp[p->i]].eType==JSON_OBJECT ){
    p->i += 2;
  }else{
    p->i++;
  }
  p->iRowid++;
  if( p->i<p->sParse.nNode ){
    JsonNode *pUp = &p->sParse.aNode[p->sParse.aUp[p->i]];
    p->eType = pUp->eType;
    if( pUp->eType==JSON_ARRAY ) pUp->u.iKey++;
    if( p->sParse.aNode[p->i].eType==JSON_ARRAY ){
      p->sParse.aNode[p->i].u.iKey = 0;
    }
  }
  return SQLITE_OK;
}

/* Advance the cursor to the next element for json_each() */
static int jsonEachNextEach(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  switch( p->eType ){
    case JSON_ARRAY: {
      p->i += jsonNodeSize(&p->sParse.aNode[p->i]);
      p->iRowid++;
      break;
    }
    case JSON_OBJECT: {
      p->i += 1 + jsonNodeSize(&p->sParse.aNode[p->i+1]);
      p->iRowid++;
      break;
    }
    default: {
      p->i = p->iEnd;
      break;
    }
  }
  return SQLITE_OK;
}

/* Return the value of a column */
static int jsonEachColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  JsonNode *pThis = &p->sParse.aNode[p->i];
  switch( i ){
    case JEACH_KEY: {
      if( p->eType==JSON_OBJECT ){
        jsonReturn(pThis, ctx, 0);
      }else if( p->eType==JSON_ARRAY ){
        u32 iKey;
        if( p->bRecursive ){
          if( p->iRowid==0 ) break;
          iKey = p->sParse.aNode[p->sParse.aUp[p->i]].u.iKey - 1;
        }else{
          iKey = p->iRowid;
        }
        sqlite3_result_int64(ctx, iKey);
      }
      break;
    }
    case JEACH_VALUE: {
      if( p->eType==JSON_OBJECT ) pThis++;
      jsonReturn(pThis, ctx, 0);
      break;
    }
    case JEACH_TYPE: {
      if( p->eType==JSON_OBJECT ) pThis++;
      sqlite3_result_text(ctx, jsonType[pThis->eType], -1, SQLITE_STATIC);
      break;
    }
    case JEACH_ATOM: {
      if( p->eType==JSON_OBJECT ) pThis++;
      if( pThis->eType>=JSON_ARRAY ) break;
      jsonReturn(pThis, ctx, 0);
      break;
    }
    case JEACH_ID: {
      sqlite3_result_int64(ctx, p->i + (p->eType==JSON_OBJECT));
      break;
    }
    case JEACH_PARENT: {
      if( p->i>0 && p->bRecursive ){
        sqlite3_result_int64(ctx, p->sParse.aUp[p->i]);
      }
      break;
    }
    case JEACH_PATH: {
      const char *zPath = p->zPath;
      if( zPath==0 ) zPath = "$";
      sqlite3_result_text(ctx, zPath, -1, SQLITE_STATIC);
      break;
    }
    default: {
      assert( i==JEACH_JSON );
      sqlite3_result_text(ctx, p->sParse.zJson, -1, SQLITE_STATIC);
      break;
    }
  }
  return SQLITE_OK;
}

      case JEACH_JSON:   jsonIdx = i;    break;
      case JEACH_PATH:   pathIdx = i;    break;
      default:           /* no-op */     break;
    }
  }
  if( jsonIdx<0 ){
    pIdxInfo->idxNum = 0;
    pIdxInfo->estimatedCost = 1e99;
  }else{
    pIdxInfo->estimatedCost = 1.0;
    pIdxInfo->aConstraintUsage[jsonIdx].argvIndex = 1;
    pIdxInfo->aConstraintUsage[jsonIdx].omit = 1;
    if( pathIdx<0 ){
      pIdxInfo->idxNum = 1;
    }else{
      pIdxInfo->aConstraintUsage[pathIdx].argvIndex = 2;
      pIdxInfo->aConstraintUsage[pathIdx].omit = 1;

    zPath = (const char*)sqlite3_value_text(argv[1]);
    if( zPath==0 || zPath[0]!='$' ) return SQLITE_OK;
  }
  n = sqlite3_value_bytes(argv[0]);
  p->zJson = sqlite3_malloc( n+1 );
  if( p->zJson==0 ) return SQLITE_NOMEM;
  memcpy(p->zJson, z, n+1);
  if( jsonParse(&p->sParse, p->zJson) 
   || (p->bRecursive && jsonParseFindParents(&p->sParse))
  ){
    jsonEachCursorReset(p);
  }else{
    JsonNode *pNode;
    if( idxNum==3 ){
      n = sqlite3_value_bytes(argv[1]);
      p->zPath = sqlite3_malloc( n+1 );
      if( p->zPath==0 ) return SQLITE_NOMEM;

static sqlite3_module jsonEachModule = {
  0,                         /* iVersion */
  0,                         /* xCreate */
  jsonEachConnect,           /* xConnect */
  jsonEachBestIndex,         /* xBestIndex */
  jsonEachDisconnect,        /* xDisconnect */
  0,                         /* xDestroy */
  jsonEachOpenEach,          /* xOpen - open a cursor */
  jsonEachClose,             /* xClose - close a cursor */
  jsonEachFilter,            /* xFilter - configure scan constraints */
  jsonEachNextEach,          /* xNext - advance a cursor */
  jsonEachEof,               /* xEof - check for end of scan */
  jsonEachColumn,            /* xColumn - read data */
  jsonEachRowid,             /* xRowid - read data */
  0,                         /* xUpdate */
  0,                         /* xBegin */
  0,                         /* xSync */
  0,                         /* xCommit */
  0,                         /* xRollback */
  0,                         /* xFindMethod */
  0,                         /* xRename */
};

/* The methods of the json_tree virtual table. */
static sqlite3_module jsonTreeModule = {
  0,                         /* iVersion */
  0,                         /* xCreate */
  jsonEachConnect,           /* xConnect */
  jsonEachBestIndex,         /* xBestIndex */
  jsonEachDisconnect,        /* xDisconnect */
  0,                         /* xDestroy */
  jsonEachOpenTree,          /* xOpen - open a cursor */
  jsonEachClose,             /* xClose - close a cursor */
  jsonEachFilter,            /* xFilter - configure scan constraints */
  jsonEachNextTree,          /* xNext - advance a cursor */
  jsonEachEof,               /* xEof - check for end of scan */
  jsonEachColumn,            /* xColumn - read data */
  jsonEachRowid,             /* xRowid - read data */
  0,                         /* xUpdate */
  0,                         /* xBegin */
  0,                         /* xSync */
  0,                         /* xCommit */
  0,                         /* xRollback */
  0,                         /* xFindMethod */
  0,                         /* xRename */
};

/****************************************************************************
** The following routine is the only publically visible identifier in this
** file.  Call the following routine in order to register the various SQL
** functions and the virtual table implemented by this file.
****************************************************************************/

#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_json_init(
  sqlite3 *db, 
  char **pzErrMsg, 

#if SQLITE_DEBUG
    /* DEBUG and TESTING functions */
    { "json_parse",           1, 0,   jsonParseFunc         },
    { "json_test1",           1, 0,   jsonTest1Func         },
    { "json_nodecount",       1, 0,   jsonNodeCountFunc     },
#endif
  };
  static const struct {
     const char *zName;
     sqlite3_module *pModule;
  } aMod[] = {
    { "json_each",            &jsonEachModule               },
    { "json_tree",            &jsonTreeModule               },
  };
  SQLITE_EXTENSION_INIT2(pApi);
  (void)pzErrMsg;  /* Unused parameter */
  for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){
    rc = sqlite3_create_function(db, aFunc[i].zName, aFunc[i].nArg,
                                 SQLITE_UTF8 | SQLITE_DETERMINISTIC, 
                                 (void*)&aFunc[i].flag,
                                 aFunc[i].xFunc, 0, 0);
  }
  for(i=0; i<sizeof(aMod)/sizeof(aMod[0]) && rc==SQLITE_OK; i++){
    rc = sqlite3_create_module(db, aMod[i].zName, aMod[i].pModule, 0);
  }
  return rc;
}